Abstract

This study aimed at investigating the effects of environmental enrichment on various aspects of contextual processing in adult female rats. In experiment 1, simple conditioning was studied using either a training procedure allowing overshadowing of the contextual cues by signalling footshock with a discrete tone or a training procedure allowing a reduction of this overshadowing by explicitly unpairing the footshock and the tone. In experiment 2, contextual discrimination and contextual occasion-setting were assessed. Rats were daily exposed to two different contexts. In one context, a footshock was delivered 30 s after the offset of a tone, whereas in the other context the same tone was presented alone. Experiment 3 examined familiarization to a new context. Experiment 1 showed that environmental enrichment reduced the overshadowing of contextual cues by the tone and also reduced freezing to the more predictive cue according to the training procedure used. Experiment 2 showed that environmental enrichment increased the ability of rats to discriminate two contexts. Experiment 3 showed that enriched rats familiarized faster to a new context than standard rats. Taken together, these results suggest that environmental enrichment in adult rats enhances learning about contextual cues and reduces overall fear associated with aversive events.